There has recently appeared a mobile phone provided with a touch panel serving as a user interface. This mobile phone may suffer a malfunction, while being carried for example, when the touch panel comes into contact with an external object. Thus, a technique is known which locks the touch panel by a switch that is provided independently from the touch panel (see, for example, Patent Document 1).
This technique however requires a user to turn on the switch in order to use the touch panel, leading to complicated operations.    [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-268776